From 57dd8a94c08351605823acfe874f94819d19bad0 Mon Sep 17 00:00:00 2001
From: Yu Hao <yuhaoyu@google.com>
Date: Wed, 22 Oct 2025 15:00:12 -0700
Subject: [PATCH] [clang][transformer] Change `name` range-selector to return
 `Error` instead of an invalid range.

Previously, when the text in selected range was different from the decl's name, `name` returned an invalid range, which could cause crashes if `name` was nested in other range selectors that  assumed always valid ranges. With this change, `name` returns an `Error` if it can't get the range.
---
 .../lib/Tooling/Transformer/RangeSelector.cpp |  8 ++++--
 clang/unittests/Tooling/RangeSelectorTest.cpp | 25 +++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Tooling/Transformer/RangeSelector.cpp b/clang/lib/Tooling/Transformer/RangeSelector.cpp
index 171c786bc366f..b4bdec1fcdd69 100644
--- a/clang/lib/Tooling/Transformer/RangeSelector.cpp
+++ b/clang/lib/Tooling/Transformer/RangeSelector.cpp
@@ -205,8 +205,12 @@ RangeSelector transformer::name(std::string ID) {
       // `foo<int>` for which this range will be too short.  Doing so will
       // require subcasing `NamedDecl`, because it doesn't provide virtual
       // access to the \c DeclarationNameInfo.
-      if (tooling::getText(R, *Result.Context) != D->getName())
-        return CharSourceRange();
+      StringRef Text = tooling::getText(R, *Result.Context);
+      if (Text != D->getName())
+        return llvm::make_error<StringError>(
+            llvm::errc::not_supported,
+            "range selected by name(node id=" + ID + "): '" + Text +
+                "' is different from decl name '" + D->getName() + "'");
       return R;
     }
     if (const auto *E = Node.get<DeclRefExpr>()) {
diff --git a/clang/unittests/Tooling/RangeSelectorTest.cpp b/clang/unittests/Tooling/RangeSelectorTest.cpp
index adf5e74ea3192..a1fcbb023832f 100644
--- a/clang/unittests/Tooling/RangeSelectorTest.cpp
+++ b/clang/unittests/Tooling/RangeSelectorTest.cpp
@@ -527,6 +527,31 @@ TEST(RangeSelectorTest, NameOpDeclRefError) {
           AllOf(HasSubstr(Ref), HasSubstr("requires property 'identifier'")))));
 }
 
+TEST(RangeSelectorTest, NameOpDeclInMacroArg) {
+  StringRef Code = R"cc(
+  #define MACRO(name) int name;
+  MACRO(x)
+  )cc";
+  const char *ID = "id";
+  TestMatch Match = matchCode(Code, varDecl().bind(ID));
+  EXPECT_THAT_EXPECTED(select(name(ID), Match), HasValue("x"));
+}
+
+TEST(RangeSelectorTest, NameOpDeclInMacroBodyError) {
+  StringRef Code = R"cc(
+  #define MACRO int x;
+  MACRO
+  )cc";
+  const char *ID = "id";
+  TestMatch Match = matchCode(Code, varDecl().bind(ID));
+  EXPECT_THAT_EXPECTED(
+      name(ID)(Match.Result),
+      Failed<StringError>(testing::Property(
+          &StringError::getMessage,
+          AllOf(HasSubstr("range selected by name(node id="),
+                HasSubstr("' is different from decl name 'x'")))));
+}
+
 TEST(RangeSelectorTest, CallArgsOp) {
   const StringRef Code = R"cc(
     struct C {